Measured-service telephone system.



T. G. MARTIN. MEASURED SERVICE TELEPHONE SYSTEM.

Pabented Oct hum/701?.-

M/[T/YESSES T. G. MARTIN. MEASURED SERVICE TELEPHONE SYSTEM. APPLICATIONFILED DEC.26, 19:3.

1,243,749.. Patented 00. 23,1917.

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' TALBOT e. MARTIN, on CHICAGO, ILLINOIS, ASSIGNOR To AUToMAT c'ELEoTRIcCOMPANY, or GEICAGQ, ILLINOIS, A CORPORATION or ILLINOIS;

MEASURED-SERVICE TELEPHONE SYSTEIVL To all whom it may concern) Be itknown that I, TALBOT G. MARTIN,

a citizen of the United States of America,

phone Systems, of which the following is a specification.

My invention relates to improvements in measured service telephonesystems, and more particularly to improved means for recording theactual time during which a talking connection between two subscribersstations is established. I

More particularly my invention relates to a time recording mechanismwhich is controlled by a clock mechanism so as to be intermittentlyoperated at predetermined intervals of time, this recording mechanismbeing started in operation by the response of the called subscriber andthe operation being stopped when the connection is .released.

My present invention provides means for operating the meter by means ofa reversal of current over the conductors of the talking circuit uponthe response of the called subscriber. 7

My invention will be more clearly understood by reference to theaccompanying drawings, in which, for the purpose of illustration, I haveshown my invention in connection with an automatic telephone system of awell-known type, although, of course, it will be understood that myinvention is not in any way limited to use in connection with anyparticular type of telephone system.

Figures 1 and 2 taken together show a complete circuit connectionbetween a call-' ing substation A and a called substation A in a systemembodying the principles of my invention. I

The central oflice equipment shown herein comprises only the socalledline switches and connector switch, but it will be clearly understood bythose versed in the art that so-call'ed selector switches may beinserted in the system, thereby increasing the capacity of the exchangewithout departing from the principles of my invention.- The saidselector switches may boot a type similar to the selector switches shownin British patent to T. G. Martin No. 1419 of 1910.

'The substation A shown herein may be Specification of Letters Patent.Patented Oct; 23 1917,

Application filed December 2c, 1913. Serial No. 808,852. l

of any suitable or approved type and comprises the usual receiver 2,transmitter 3, ringer 4 and condenser 5. Being a so-called automaticsubstation it is also provided with an impulse transmitter or callingdevice, which is herein represented by a pair of impulse springs 6 and 7and an impulse wheel 8, which latter is assumed to be controlled throughthe medium of a finger hole d1al (not shown) in such a manner that theimpulse springs 6 and 7 may be momentarily separated a number oftimescorresponding to each digit of the number to be called.

The subscribers individual switch C is of the general type ofsubscribers switch shown in British patent to R. W. James No. 26,301 of1906, being, however, of the particular type disclosed in theabove-mentioned British Patent No. 1419 of 1910. This line switchcomprises, among other details, a plunger (not shown) attached to theend of a so-called plunger arm-1O which is controlled by the magnet 11.The magnet 11 comprises four windings, namely, a pulldown winding 12, acut-off or holding Wind'- ing 13, a line winding 14 and an auxiliarywinding 15. The core of the magnet 11 is so constructed that themagnetic circuit of the windings 12 and 13 is separatefrom that of thewindings 14 and 15. The winding 12 operates both the plunger arm 10 andthe cut-off armature 16, while the winding 18 is only strong enough tooperate the-cut ofl armature 16 and to hold the plunger arm 10 in itsoperated position. When the plunger arm 10 is operated, the plunger is fforced into a bank of contact springs, forcing the springs 17 18, 19 and20 into engagement with the springs 21, 22, 23 and 24, respectively.Although only one set of springs (17 to 24) is shown, each ,line switchis provided with a" plurality of such sets, each set forming theterminal of a trunk line leading to a connector switch H. Each trunkline isv connected in multiple with the corresponding springs of all theline switches British Patent No. 1419 of 1910. The function of themaster switch, as is well known, is to maintain the plungers of all theidle line switches in position to engage the terminal of an idle trunkline.

The connector switch H is of the same general type of connector switchasdisclosed in United States Letters Patent No. 815,176, granted March13, 1906, 'toKeith, Erickson and Erickson, the circuits, however, beingmodified to adapt the switch to operate in a system in whichthe centraloiiice apparatus is controlled by impulses delivered over the two sidesof the line in series. The connector is provided with a shaft (notshown) car- I in the wi ers 25 26 and 27 which shaft is controlled bythe vertical magnet 28 and the rotary magnet 29. The usual side switchcomprising the wipers 30, 31, 32 and 33 is controlled by the privatemagnet 34: in the usual well-known manner. The magnet 19 is the usualrelease magnet. The line relay 35 is connected with the calling linethrough the reversing springs of the so=called backbridge relay 36. Theringing relay 37 is the means through which ringing current is appliedto the called line.

The called substation A, togetherwith its individual switch C, issimilar in all respects to the substation A, together with itsindividual switch C.

For the purpose of supplying battery current for operating the centraloilice apparatus and for talking purposes there is shown a battery 13having one terminal grounded. The usual busy signaling machine is shownat L.

Associated with ,theline switch C of ,the calling line is a timerecording meter M controlled by the meter magnet 72. The1cir cuit ofthis .magnet is in turn controlled by the meter relay 50 and by a clockmechanism K. This clock mechanism is arranged so as to intermittentlyopen and close the contacts 51 and 52 and in this manner control theconnection of the magnet 72 to battery B. The relay 50 is a double-woundrelay, the windings being so proportionedthat it requires theenergizationof both windings in the same direction to attract itsarmature,

said armature being unaffected by the energization of either windingalone, or by the energization of the two windings in opposition to eachother. By this arrangement, when the meter relay 50 is operated upon theresponse of the called subscriber, in a manner to be hereinafterdescribed, to close the circuit of the meter magnet 7 2, the clock imechanism .1: then operates to intermittently operate the magnet 72 andthus cause the meter to accurately register the time consumed by theestablished connection.

A general description of the apparatus having been given, in order togive a complete understanding of my invention I will now describe howthe calling subscriber at the substation A may obtain connection withthe subscriber at the called substation A, and how the meter M willoperate to regis ter the length of time that the conversation is held.It will be assumed that the number ofthe called substation is 20.

Upon the removal of the receiver from the switch hookatthe substation Apreparatory to making a call, an energizing circuit is closed throughthe line winding 14; ofthe individual switch C, thereby attracting theline armature 38. The armature 38, upon being attracted, closes acircuit through the pull-down winding 12 in series with the auxiliarywinding '15. The pull-down winding 12, upon energizing, attracts theplunger arm 10 to force the plunger into the bank of springs 17 to 24,inclusive. It also operates the cut-oii armature 16, therebydisconnecting the line winding 14 from the-line. The armature 38 doesnot fall back immediately, however, owing to the fact thatthe winding 15is still in series with the pull-down winding 12. Upon the plunger arm10 being attracted, the springs 39 and 40 are brought together toshort-circuit the auxiliary winding l5, making the same slightly slowacting. At the same time the springs 39 and 10 make contact, the springs41 and 42 are brought together, closing a circuit through the right-handwindingof the relay 50, said circuit extending from ground G through thesaidwinding and the contact of springs 41 and 4:2 to battery B,=thencethrough cattery B ,to ground G; but the armature of the relay 50 isunaifectedby the energization of this winding alone. The armature 38being slow to fall back allows sufficient time for a holding circuit tobe closed in the switch ahead for the cut-oil or holding winding 13. Theen agement of the springs 17 and 20 with the springs 18 and 21,respectively, extends thesubseribers lines to-the line relay 35 oftheconnector 'E.

This circuit extends through the left-hand winding of-the magnet 50, butdoes not operatively energize said magnet, as the two windings areacting in opposition to each other. The line relay 35 of the'conneetorswitch E is thereupon energized, closin a circuit through the slowacting relay 43. The relay 43, upon energizing, closes theabove-mentioned holding circuit through the cut-off winding 13 of theline switch C. This circuit extends from ground G through the contact ofsprings 4%, bank springs 22 and 18 and'the cut-off -winding"13 tobattery B. The winding 13, upon energizing, holds the cut-off armature16 and the plunger arm 10 in their operated positions after the circuitof the pull-in winding is broken by the falling back of the iinearmature 38. A guarding ground potential is supplied to the connectorprivate bank contacts of the calling line as soon as the relay 43isenergized. This potential extends over the circuit just traced to thebank contact 18, thence over the conductor 45 to said private bankcontact. The energization of the relay 43 also prepares a circuit forthe vertical magnet 28 by bringing into engagement the springs 46 and 47and opens the circuit of the release magnet 49 at the springs 47 and 48.

The calling subscriber now operates his calling device for the firstdigit 2 of the called number, whereby the substation impulse springs 6and 7 are operated twice -momentarily, each time breaking the circuit ofthe connector line relay 35. The relay 43 of the connector switch beingslow acting does not deenergize during the momentary interruptions ofits circuit by the line relay 35, and consequently, each time the latterrelay deenergizes, an impulse is transmitted over the circuit extendingfrom ground G through the contact of springs 55 and 54, springs 47 and46 of the relay 43, slow acting relay 57, vertical magnet 28 and theside switch wiper 30 (in first position) to battery B. The verticalmagnet receives two impulses over this circuit and operates to raise theswitch shaft and wipers to a position opposite the second level of bankcontacts. The relay 57, which was included in series with the. verticalmagnet, remains in its energized position during the entiretime thatimpulses are being transmitted through it and operates to close thecircuit of the private magnet 34. This circuit extends from ground G4through the contact of springs 60 and 58 and the said relay to batteryB. After the last impulse is delivered, the relay 57 opens the circuitof the private magnet 34, which, upon deenergizing, permits the sideswitch to advance from first to second position in a well-known manner.'The movement of the side switch wiper 30 from first to second positiontransfers the battery connection from the ver-- tical magnet 28 to therotary magnet 29. The calling subscriber now operates his calling devicefor the last digit 0, in response to which the connector line relayoperates to transmit ten impulses through the rotary magnet 29 in serieswith the relay 57, whereby the shaft and wipers are rotated onto the Icontacts of the desired line. This circuit extends fromv ground Grthrough the contact of springs 55 and 54, springs 47 and 46, relay 57,springs 61, rotary magnet 29 and the side switch wiper 30 (in secondposition) to battery B. If the called line is idle, the private magnet34 deenergizes when its circuit isbrokenby the relay 57 after the last.impulse 'is delivered to the rotary magnet 29. The deenergization of theprivate magnet 34 allows the side switch to advance one more posit1onthat1s, from sec-n the energization of the bridge-cut-ofi winding 62 ofthe line switch C, the connection is completed withthe' calledsubstation. The circuit for the bridge-out-off ,winding 62 of the lineswitch Gextends from ground G through the side switch wiper 31 (in thirdposition), private wiper 26, conductor 63 and the said cut-off windingto the battery lead 100. ergizing, operates to disconnect the linewinding 64 of the line switch 0. from the line and to extend the linethrough to the called substation A. A guarding ground potential issupplied to the connector private bank contact of the called line, whichprevents the called line from being seized by some other connectorswitch. By the engagement of the side switch wiper 30 with itsthird-position contact point, the circuit of the ringing relay 37 isclosed. Thiscircuit extends from ground G through the interrupter 65,relay 37, springs 66 and the side switch wiper 30 (in third position) tobattery B. The ringing relay, upon ener gizing, disconnects the calledlinefrom the calling line and bridges the ringing generator R across thecalled line. The ringing relay is energized only intermittently throughthe medium of the interrupter 65.

Upon the response ofthe called subscriber his line is provided withtalking current through the back-bridge relay 36. The relay 36, uponenergizing, closes the circuit of the ringer cut-off relay 67. Thiscircuit extends from ground G through the side switch wiper 31 (in thirdposition), contact of the springs 68 and the relay 67 to battery B. Therelay 67, upon energizing, interrupts the circuit of the ringer relay 37at the springs 66 and closes alocking circuit for itself through thesprings 70 independent of the springs 68. A further result of theenergization of the back-bridge relay 36 upon the response of the calledsubscriber is. the reversal of the connection ofthe windings of the linerelay- 35 to the conductors 84 and 85, whereby the direction of thecurrent in the calling line is re versed, and consequently in theleft-hand winding ofthe relay 50. This reversal of current in theleft-hand winding of the res. lay 50 causes thetwo windings of thisrelay to now assist eachother and to operatively energize the saidrelay, which upon energizing, closes the circuit for the meter magnet 72and closes the contact of springs 71, whereby the left-hand winding ofsaid'relay is short-circuited. The relay is then held in its operatedposition by thev righthand winding alone, which, although it is notstrong enough to operatively energize the relay, is strong enoughtohold'it when The said winding, upon en 1.

inits operatedposition, The short-circuiting: of the left-hand windingrenders the meter magnet inoperative to any changes in the line current.The said circuit for the magnet 72 extends from ground G throughthe'contact of springs 73,:met'er magnet .72 and the springs 51 and 52-(controlled by the clock K) to battery B. Thismaster' clock K operatesto intermittently openthe springs 51 and 52 and this causes theintermittent operation of the meter M; The clock being adjusted so as toclose these springs at predetermined time interva-ls,the meter operatesto accurately register the time of the talking connection.

After the conversation is completed, the connection is released by thehanging upof the receiver at the calling substation in the usual mannerand the magnet 50 deenergizes and the circuit of the meter magnet 72 isopened 1 at, the spring 73.

If the called line is busy, there will be a guarding potential upon theconnector private bank contact, just as explained in connection with theline switch C. When the connector private w1per'26 engages this guardingcontact,a busy signal is sent back to the calling line from the busysignaling machine L inthe well-known manner. The subscriber, hearing thebusy signal, replaces his receiver upon the receiver hook and thusreleases the apparatus.

It will thus be seen that I have devised a very simple and ei'licient'arrangement for measuring the length of time that a conversation iscarried on. It will also be seen that the calling subscribers registerbegins to operate only when the called subscriber responds, so that thesubscriber is not charged with the time taken to set up a connection,

or for the called subscriber to answer, but

is charged only from the time that conversation begins.

While I have illustrated the registering devices associated withautomatic switches in connection with an automatic telephone exchangesystem of aparticular type, it is, of course, understood that myinvention is not limited to use in such a system. The

registerim device may be employed with any suitable automatic system,and in its broader aspect my invention may be employed in connectionwith either manual or semi-automatic systems.

What I claim as my invention is 1. In a telephone system, a plurality ofsubscribers lines, means for establishing lation of said last=mea nstothetalkingcir cuit, another winding for said means controlled overacircuit individual to the calling line, and aclock mechanismfor furthercontrollingthe operation of saidmeter.

2. In a telephone system, aplurality of subscribers lines, means forestablishingi connection between t wo'of said lines, a time recordingmeter associated with the' ca-lling i line, means for reversing thecurrent in the; calling line upon the response of the called subscriber,means having a winding in se' ries withthe talking circuit conductors,controlled by said reversal of current for initially operating saidmeterand for changing the relation of said last means to the talking circuit,another winding for said means controlled over a circuit individual tothe calling line, and a clock mechanism for intermittently operatingsaid meter at predetermined time intervals after saidfirst operations 3.In a telephonesystem, a plurality of subscribers lines, means forestablishing connection between-two of said lines',.a-time recordingmeter associated with the calling line, a relay for controlling theoperation of said meter, said" relay'having a plurality of energizingwindings,1neans for initially energizing said windings diflerentiallywhen connection'is being extended to the called line, me'ans forreversing'the current in one of said windings upon the response of thecalled subscriber to-thereby render said relay operative to 'operate'said meter, a holding winding for said relay controlled over a circuitindividual to'thecalling line, and a clock mechanism for furtherintermittently con'trollingtlie operation of said me ter'.

li In a telephone system, a plurality of subscribers lines, meansincluding" automatic selecting and connecting switches for estabfishingconnection between'two "of said lines, a time recording meter associatedwith the callingline, means for reversing'the current in the callingline upon the response of the called subscriber, means having"- awinding in series with'the talking circuit conductors controlled by saidreversal of current for initially operating said meter and for chang ingthe relation of said last means to the talking circuit, a holdingWindingfor said means individual to the calling line, and a clockmechanism* for intermittently operating said meter at predetermined timeI in tervals after said first operation.

'5.-ln' a telephonesystem, a plurality of subscribers lines, means forestablishing" a talking circuit between-tweet said lines, a timerecording meter associated with the calling line, a relay forc'ontrolling the operation of said meter, said relay having a pluralityof energizing= w'indings, one of said windings beingin series "with"said talking circuit, and another of said windings being permanentlyconnected to one terminal of battery, means for initially energizingsaid windings differentially when connection is being extended to thecalled line, means for reversing the current in one of said windingsupon the response of the called subscriber to thereby render said relayoperative to operate said meter, a clock mechanism for furthercontrolling the operation of said meter, and means for deenergizing saidrelay to render said meter inoperative when the connection is released.

6. In a telephone system, calling and called subscribers lines, a timerecording meter individual to each. calling line, means for establishinga talking circuit between two of said lines comprising an automaticswitch individual to a calling line and an automatic switch common tothe calling lines, a relay for controlling the operation of said meter,an energizing winding for said relay controlled exclusively over acircuit local to said individual switch, another energizing winding forsaid relay including a portion of the talking circuit controlled by saidcommon switch to thereby control the operation of said meter, and aclock mechanism for further controlling the operation of said meter.

7 In a telephone system, calling and called lines, a time recordingmeter individual to each calling line, means for establishing a talkingcircuit between two of said lines comprising an automatic switchindividual to the calling line and an automatic switch common to thecalling lines, a relay for controlling the operation of said meter, awinding for said relay energized over a circuit exclusive of said commonswitch, another winding for said relay con trolled over a portion ofsaidtalking circuit, by said common switch to thereby control the operationof said meter, and a clock mechanism for further controlling theoperation of said meter.

8. In a telephone system, a plurality of subscribers lines, means forestablishing connection between two of said lines including a linkcommon to said lines, a time recording meter associated with the callingline, a relay for controlling the operation of said meter, said relayhaving a plurality of energizing windings, means for initiallyenergizing said windings differentially when connection is beingextended to the called line, means for reversing the current in one ofsaid windings upon the response of the called subscriber to therebyrender said relay operative to operate said meter, one of said windingscontrolled over a circuit exclusive of said link, and a clock mechanismfor further controlling said meter.

Signed by me at Chicago, Cook county, Illinois, this 15th day ofDecember, 1913.

TALBOT Gr. MARTIN.

Witnesses:

HARRY E. HERSHEY, B. GARBER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

